Air brake adjusting tool



June 22, 1954 c. F. HAHN AIR BRAKE ADJUSTING TOOL Filed Jan. 14, 1952 IN V EN TOR.

(Ila/131'] Hahn Patented June 22, 1954 AIR'BRAKE ADJUSTING TOOL Clair F. =Ha2hn, Canton, Ohio 'Applicationqanuai'y14, 1952, "Serial No. 266,427

2 Claims. 1

Theinven-tion' relates to-a' tool for adjusting air brakes (in trucks," tractor=trai1ersandthe like, and more particularly to such a tool "comprising a metalbar havinga hook pivotally connected to one side thereof near'oneend of the bar.

Vin-"brakes of the type-referred to have-a lever armppon "each wheel brake; said lever arm being connected bya link'tothe usual air brake dia- "phragmby meanspfwhich' thebrakes'are oper- Q 'ated.

'Due to wear upon thebrake shoes, caused by "operation'of the brakes, acertain amount of lost motion,'or p1ay,"devel'ops in these lever'arms, necessitating frequentfadjustment of the brakes to take out unnecessary lost motion.

' Under present practice thisrequires the servicesof two"men,"one -seatedin the cab of the vehicleto operate the-brakes, and the other lo- "ca-tedbeneath the vehicle-sothat hecan see'the "amount'of play, or lost motion,-ineach lever arm and thenmake the required adjustment to' removeany unnecessary lostm'otion from each lever arm.

"It is an objector the'present invention to providea tool by means ofwhich one'mechanic may 5:25

*independen-tly move each lever arm, to determine "the 'aimount"of"lost motion thereinand then make "the required adjustment 'to remove unnecessary lost "motion therefrom.

may be used in adjusting the brake after the amount of'lost motion has been determined.

"A further object is to provide a tool of the characterreferred to comprising a metal "bar having '"a hook pivotally connected to one side of the bar;

near one end thereof, the hook being-of such length that it may be swung over the adjacent ehdof thebar, soas" to be disposed upon either side of the bar-toprovideeitherna long or a short hook as may be required.

-A still further object of'lthe inventionis topro- "vide sucha tool in which'theend portion of the bar, adjacent .to the hook,-is-tapered and provided with a-slightly concaved terminal-end, 'ior engaging and forcing inwardly the usual sleeve-whichnormally prevents rotation of the worm screw in the lever arm.

The above objects together with others which will be apparent from the drawing and following description, or which may be later referred to, may be attained by constructing the improved tool in the manner hereinafter described in detail and illustrated in the accompanying drawing, in which:

Fig. 1 is a side elevation of the tool, showing broken away; showing the manner in which 'the tool is used'to push inwardly; to released-position, the sleeve which normally prevents iotationbf the "worm screw and,

Fig. 5 an edgeviewo'f a portion of-the--*lever arm'showing the end of theworm screwarid the sleeve which preventsrotation thereof.

In the ordinary construction of air brakes for vehicles, a leverarm, indicated generally-at i0; is

associated with each wheel brake, this lever arm being fulcrumed as" at I l,and-adapted 'to=- be'oscillated-around the fulcrum-by mea-nsof *a' link 12 which connects the lever arm to the diaphragm of the air brake operating mechanism.

"Each =lever arm has '-a. worm screw "13 flour-- "nalled therein,which engages a worm wheeli'not shown) within theenlarged head lawman is pro- "vided, as in common practice "in such brakes, for Another object is" to provide such'atoohwhichty adjusting the brake-shoe upon the corresponding wheel.

For the purpose of normally preventing the "worm screw I3 I from rotating, asleeve I 5 18351111- ably located within the transversely dis-posed *boss 1 6 upon one side of thelever-arm; thissle'eve having a hexagonal interior, as indicated *at- 11,

'for norm-ally engaging the'hexagonal heads upon the outer end of theworm screw.

A coil-spring I9 is usually provided for ur'g'ing 0 the s1eeve l5 outward, as showni'n fu ll lines in Fig;4,-so-that the hexagonal interior therefengages the hexagonal head 18 of the worm screw.

A-keyllll' is provided ilo prevent 'rotation-of the sleeve 15.

The improved toolto which-theinvention pertains comprises a straight bar Zipprftably formed 'of-steel, having-a handle-'orlharidigrip 22 at its lower end, the upper end portion being referably tapered or reduced in thickness, as indicated at 23, and terminating in the concave, arcuate end 24, for a purpose to be later explained.

A lug '25 is formed at one side of the bar 2|. at a point spaced from the upper end thereof, to provide a support for the pivot pin 26 upon which the hook '21 is mounted. This hook is of such 3 length that it will just clear the end of the bar 2 1, as indicated in Fig. 2, so that the hook may be swung over the end of the bar to be disposed at either side of the bar as occasion may require.

As shown in Fig. 1, the hook 2! is shown in full lines at the left side of the bar 2|, this being the side upon which the hook is pivoted. Thus a relatively long hook is provided. In cases where a shorter hook is desirable the hook may be swung over the end of the bar and disposed on the right side of the bar 2 I, as indicated in broken lines in Fig. 1.

When the tool is used in adjusting a brake, in order to first determine the amount of lost motion or play in the lever arm I0, the hook 21 is engaged over one side of the lever arm 10 and the upper end portion 23 of the bar 2| is engaged against the opposite side of the lever arm, as shown in Fig. 3, and the handle portion of the tool is then pulled to the right, as indicated by the arrow in Fig. 3.

This provides sufiicient leverage to swing the lever arm l upon its fulcrum, and the mechanic may thus determine the amount of unnecessary lost motion which must be compensated for. In order to adjust the brake to take up the lost motion, the sleeve 15 must be pushed inward, against the pressure of the spring 19, until it is disengaged from the hexagonal head 18 of the Worm screw 13, in order that the worm screw may be rotated to make the adjustment.

7 This sleeve is frequently very hard to push inward as the same often becomes corroded from salt and other chemicals which may be placed upon streets and highways to melt snow and ice.

The tool to which the invention pertains is adapted for quickly and easily pushing this sleeve inward, out of engagement with the hexagonal head of the worm screw, as shown in Fig. 4. The hook 21 is engaged over the opposite side of the lever arm is and the upper end portion of the bar 2| is engaged against the outer end of the sleeve IS, the concaved end 24 of the bar accommodating the hexagonal head iii of the worm screw.

The bar 21 is then pulled to the right, as indicated by the arrow in Fig. 4, providing considerable leverage which will easily loosen the sleeve 15 and force it inwardly to the broken line position, out of engagement with the hexagonal head A socket wrench or the like may be applied to the hexagonal head of the worm screw to adjust the same to take up the unnecessary lost motion. It will thus be seen that with the tool one man can quickly and easily determine the amount of lost motion to be compensated for in the lever arm of each wheel brake and then quickly and easily make the desired adjustment.

In the foregoing description, certain terms have been used for brevity, clearness and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example, and the scope of the present invention is not limited to the exact details of construction.

Having now described the invention or discovery, the construction, the operation, and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby; the new and useful constructions, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

I claim:

1. A brake adjusting. tool comprising a substantially straight bar having one end portion thereof flattened on two opposite sides, a lug disposed outwardly from the bar on one of said two 7 sides at a point spaced from said one end thereof, a pivot pin carried by said lug and extending from one side of the lug at right angles thereto, and a hook lever pivoted upon said pivot pin and movable around said pivot pin only in a plane parallel with the bar, said hook lever being of a length slightly greater than the distance from the pivot pin to said one end of the bar and having an angular hooked end extending to a point on the opposite side of said bar from the pivot pin and terminating in a backwardly disposed end, whereby the hook lever may be swung over said one end of the bar so that it may be disposed upon either of said first mentioned two sides of the bar with the hooked end thereof located closer to the axis of the bar in one position than in the other position.

2. A brake adjusting tool comprising a substantially straight bar having one end portion thereof flattened on two opposite sides and terminating in transversely concaved arcuate end, a lug disposed outwardly from the bar on one of said sides at a point spaced from said one end thereof, a pivot pin carried by said lug and extending from one side of the lug at right angles thereto, and a hook lever pivoted upon said pivot pin and movable around said pivot pin only in a plane parallel with the bar, said hook lever being of a length slightly greater than the distance from the pivot pin to said one end of the bar and having an angular hooked end extending to a point on the opposite side of said bar from the pivot pin and terminating in a backwardly disposed end, whereby the hook lever may be swung over said one end of the bar so that it may be disposed upon either of said first mentioned two sides of the bar with the hooked end thereof located closer to the axis of the bar in one position than in the other position.

References Gited in the file of this patent UNITED STATES PATENTS Number Name Date 343,341 Robertson June 8, 1886 1,219,948 Kaehler Mar. 20, 1917 1,670,220 Thweatt May 15,1928 1,815,220 Strong July 21, 1931 1,933,756 Prescott Nov. '7, 1933 

